Various types of hydraulic knuckle-boom log loaders have been proposed or made available on the market, and some of these have been provided with winch mechanisms with relatively short cables, so that they are limited to hauling logs for relatively short distances. Attention, for example, is invited to the following prior U.S. patents of interest which relate to devices for setting telephone poles, for pulling stumps or trees, or for bunching and falling trees, and which are not suitable for the hauling of logs considerable distances: U.S. Pat. Nos. Rowe 2,290,384; Klein 2,779,486; Carbert et al. 3,189,194; Scaperotta 3,333,717; Spanger 3,576,202; and Wirt 4,126,235.
No hydraulically powered swinging boom log hauling units have been made available for hauling logs through distances of 600 feet or more. Also, no such units have been available as attachments to crawler vehicles or bulldozers, employing the power available from such vehicles. There is a definite need for a swinging boom type of log hauling machine which can be furnished as an attachment for a bulldozer or similar vehicle and which includes a hydraulically powered winch with a long cable to enable the skidding of logs up hills and for considerable distances to loading positions where they can be bucked and loaded onto a truck.